SENIOR SNP sources have warned that a second referendum on Scottish independence should not take place until at least 2020 - over fears the public could still back the Union.

SNP leader and First Minister Nicola Sturgeon is expected to address the issue of a second referendum at the SNP’s party conference in autumn.

Ms Sturgeon has repeatedly said that a second poll is not on the cards, but has hinted at a potential referendum on Scottish independence if the UK votes to leave the EU but Scotland votes to stay.

Former SNP leader and current MP Alex Salmond said last month that a second referendum is ‘inevitable’ while a host of other political figures including Labour grandee Tam Dalyell, former Scottish Labour leader Jim Murphy and ex-Justice Secretary Kenny MacAskill have all suggested a second referendum could be held within a matter of years.

Current MPs Angus MacNeil and Pete Wishart have recently spoken out on the subject, with Perth MP Mr Wishart agreeing that there would be a second referendum but admitting ‘The process of getting there is still uncertain’ while Mr MacNeil, MP for Na h-Eileanan an Iar, said that there would be another poll before 2020.

Last month, Scottish Secretary David Mundell said there were no contingency plans in place for the possibility of a second referendum on Scottish independence after next year’s Holyrood election.

But some Nationalists have voiced their concern at talk of a second referendum in the near future.

One SNP MP told The Herald that a second referendum couldn’t be mooted until the party had discussed properly ‘why we lost the last one’.

The MP added: “We can’t afford to lose another [referendum] or the cause really will be lost for a generation.”

Other party sources warned that it would be a ‘mistake’ to equate support for the SNP with support for independence, saying: “We have to go when we are absolutely sure the public is with us on this.

“We’re not there yet and probably won’t be by the end of this parliament.”